The invention pertains to electronic displays and to control circuitry for controlling the light output of these displays. In the more common type of brightness control circuit for electronic displays, the current supplied to the display elements is controlled as a function of the amount of illumination desired from the display. This is normally done by adjusting a resistance through which the energizing current flows, or by adjusting the supply voltage as applied through an emitter follower circuit. In addition to being inefficient and wasteful of energy, these forms of control have a limited range over which the illumination can be linearly controlled and tends to turn off completely at low brightness. As a related matter, the control circuit may be subject to temperature instabilities and excessive variations in component tolerances, giving rise to a nonuniform illumination from the display elements.